Plug for core drills



A. F. MCQUISTON PLUG FoRcoRE DRILLs Filed oct. 5, 19.2;5l

Nov. 26, 19,29.

Panarea Nov. 2s, 1929 vUNITED STATES PA'rEN-r OFFICE ARMEL IE"fMCQUISTON, OF TAFT, CALIFORNIA, ASSIGNOR TO ELLIOTT CORE DRILLING lCOMPANY, A CORPORATION 0F CALIFORNIA PLUG FOR CORE DRILLS- Applicationled October 5, 1928. Serial No. 810,524.

My invention relates to the art of taking cores by the rotary method ofdrilling, being more speciically a plug for temporary and partialclosure of the core receiving chamber 3 during the lowering of the drillinto the hole. In core drills of the type used in rotary drilling, the.core receiving chamber is open at its lower end and during the loweringof the drill into the hole the rotary mud or circulating fluid, togetherwith large particles of the formation, enters thevcore receivingchamber. Later when drilling operations are commenced, as the coreenters such'chamber the Huid or mud is discharged from the top of thecore tube or barrel through a valve. but any large pieces of formationaccumulate in the top of the core barrel and pack therein,thereby-diminishing the core receiving length of the core chamber assuch 0. material will not pass through the valve. Such material in someinstances packs in the barrel to such an extent as to impede theentrance ofthe core into the barrel, resulting in failure to obtain acore typical of the forma- 5 tion being drilled. A

It is the principal object of my invention' to provide a collapsibleplug of simple form andconstruction mountable in the core recelvingopening of the core barrel which is 0 positively dislodged at thetimethe drill is about to engage the formation.

Other objects and advantages will appear hereinafter from the followingdescrlption and drawings. Referring to the drawings which are forlllustrative purposes only Fig. 1 is a side elevation partly in sectioni of a core drill equipped with a form of my invention. f Fig. 2.is anenlarged vertical sectional view of the lower end of the drill shown inFig. 1. Fig. 3 is an enlarged cross sectional view of the plug with thedart removed; and

,Fig. 4 is a perspective view of the parts forming a complete plug.

More particularly describing my invention yas illustrated in thedrawings, 11 designatesl the outer barrel of a core drill to which issecured, at its lower end, a drill body having a drill head 13 threadedthereon. 'The-head lterminates at its lower end in a circular toothedcutter 14 .formed about a central core receiving opening 15 which'communicates vwith a centralcore opening 16 in the body 12 and the corechamber 17 of a core barrel 18. The core barrel 18 is spaced apart fromthe outer barrel to form a fluid circulation pas- .Sage 19 therebetween,such passage 19|having outlet ordischarge openings 20 formed in the body12. The inner or core barrel 18 is provided at its upper end with avalve 21 which permits the circulative fluid or mud to be dischargedtherefrom as the core en- A ters the core barrel.

` In' addition to the circular cutter 14 the head 13 is povided withcutting blades 22 which may be -of any desired form.

' The plug may be termed a collapsible mem-k ber and is designed to twithin the core reblocks as shown in Fig. 2 retains the plug in positionin the opening 15 of the head and prevents dislodgment `of the plug fromthe' opening until the dart engages the bottom of the hole indicated at30 in Fig-2 as hereinafter described.

vThe device operates as follows: The plug is placed in the drill in theposition shown in, full lines in Fig. 2 with the lower end` of the dartextending ahead of the lower end lof the drill. The drill is thenlowered into the hole and during sucl. lowering of the drill the plugexcludes large particles from entering the core barrel. Theopening 31between the two blocks 25, however, permits the circulatli)ng fluid ormud in .the hole to enter the core arrel.

of the blocks just described, but it is under`A stood that the adjacentfaces of the' bloclxs the dart 29 strikes the bottom of the` may be madein dierent form as long as sufcient clearance is allowed between theblocksl to rmit such collapsing movement.

e blocks and dart may be made of any suitablematerial such as wood, ironor com positions of variouskinds.

yI claim as my invention: y

1. -A tem orary plug. for core drills for insertion in t e core receivinopening of the drill comprising plug mem rs mounted in the corereceiving opening and a lplug' collapsing member mounted on said s umembers andextending ahead of said r' 2. A temploraryplug for coredrills for insertion in t e core receivin opening of the drillcomprising a collapsi "le li'lilug in the core recei'vn openingfrictiona y engaging the inner wa s thereof and means exten 'ng ahead ofthe drill for collapsing the plug. zo, 3. A temploiary plug for core forin'- serti'on in t e core receiving opening of the drill comprisingsemicircular plug members y in the core receiving o ening and a memberextending between sai plug members in tapered engagementtherewith,having its lower end extended ahead of said drill.v 4. Atemporary plug for core-drills for insertion in the core receivingopening of the v drill comprising semicircular plug members in the corereceiving o ening and a, member extending between sai plug members intapered threaded engagement therewith have ing its lowerend extendedahead of said drill.

5 A temtlorary plug for coredrills for iny sertion in e core receivingoFening of the vdrill comprising a collapsible p ug member in 'y saidcore receiving opening and a'dart member arranged to collapse said lugmember, said dart -member bein moun on said plug 40 and extending thereqw. v

In testimony whereof, I have hereunto set` my hand at Bakersfield,California, this 14th day of September-1928.

ARMEL F. MCQUISTON. t

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